The overall goal of this project is to manufacture an oil derived from algae which is enriched in omega-3 polyunsaturated fatty acids. Preliminary data have shown there is a diatom which produces a non-membrane associated triglyceride with a high content of EPA but low contents of other polyunsaturated fatty acids, and is more stable to oxidation. However, this organism is an obligate prototroph. The proposal aims to transform this strain into a heterotroph so that it can be produced by fermentation in large quantities and provide an economical source of an oil enriched in EPA. The strategy proposed is to first determine if this strain transports glucose. If it doesn't the investigators will try to transform it using the glucose transporter gene from another microorganism. If this strategy is unsuccessful, total transformation or mutagenesis and selection will be attempted. In phase 2, the procedure will be optimized using the developed strain to prepare for commercialization of a "designer oil."